In the conventional technology, a touch display screen is formed by providing a capacitive touch device on an infrastructure of a display screen, and the touch display screen includes a touch module and a display module. The touch module is provided with a touch electrode unit configured to form a touch capacitor. The display module is provided with a display electrode unit configured to implement an image display. As the capacitive touch display screen is becoming thinner, a gap between the touch electrode unit and the display electrode unit is getting smaller and has reached a micrometer scale. A capacitive effect is generated between the touch electrode unit and the display electrode unit due to the gap, such that the touch electrode unit and the display electrode unit independent from each other are influenced with each other.
Taking the case of using an active matrix organic light emitting diode display screen (hereinafter simply referred to as an AMOLED display screen) as a basis for constructing a capacitive touch display screen as an example, as shown in FIG. 14, the AMOLED touch display screen includes a display electrode unit PR2, a display medium layer PR4 and a display thin film transistor electrode substrate (simply referred to as a display TFT electrode substrate) PR5 which are stacked. A touch electrode unit PR1 is provided on the display electrode unit PR2, a thin film package layer PR3 is arranged between the display electrode unit PR2 and the touch electrode unit PR1, and a polarizer PR6 covers the touch electrode unit PR1. Taking the case where the touch electrode unit PR1 is implemented using a mutual-capacitance touch principle as an example, as shown in FIG. 15, the touch electrode unit PR1 includes a driving electrode ETX and a sensing electrode ERX. Since a thickness of the thin film package layer PR3 is less than 10 μm, a thin film package resistance and an equivalent capacitance are generated between the touch electrode unit PR1 and the display electrode unit PR2. A thin film package resistance RTXP and an equivalent capacitance CTXP are generated between the driving electrode ETX and the display electrode unit PR2, and a thin film package resistance RRXP and an equivalent capacitance CRXP are generated between the sensing electrode ERX and the display electrode unit PR2. As the AMOLED touch display screen is becoming thinner, the thickness of the thin film package layer PR3 is further reduced, resulting in low thin film package resistances RTXP and RRXP, which may cause electric leakage between the touch electrode unit PR1 and the display electrode unit PR2. Moreover, with effects of the equivalent capacitances CTXP and CRXP, a driving efficiency of the touch module is decreased due to a potential difference between a reference potential applied to the touch driving electrode unit and a reference potential applied to the display driving electrode unit. The above factors may directly result in a longer response time of the touch electrode unit to a touch event or even an inaccurate detection on occurrence of a touch event.
In particular, for some current-driven display electrode units, a potential of a display driving signal applied to a display electrode unit is dynamically adjusted based on a change in a display luminance, and the touch electrode unit is seriously impacted by a changing potential of the display driving signal, and the touch module may not reflect an actual situation of a touch accurately.